US Assisted Opening Knife Laws and Legality
Federal law does not prohibit the ownership or interstate transport of knives that allow the user to open the knife single-handedly by applying pressure to the blade. Known as assisted opening knives, they differ from switchblades or spring-loaded knives in that the user must manually begin the process of opening the knife. The blade is simply easier to open from that point due to mechanical design.
While federal law does not prohibit ownership of such knives, you are definitely prohibited from carrying them into any public building or place where security may be an issue. Signs will often be posted in these areas prohibiting the carrying of any knives, whether assisted opening or not, from being in your possession while you are in that area. Examples of these areas include airports, federal buildings, courthouses, and schools. Generally, areas where these knives are prohibited will also prohibit any item which may be used as a weapon.
States have interpreted the federal laws in various ways, and have made their own laws based on these interpretations and local opinion. Therefore, you must be familiar with the laws in the state in which you own a knife to be sure that there are no prohibitions on your knife.
Although federal law does not specify a length limit, many states do. Some states allow switchblades or other mechanically-opening knives of two inches or less, although federal law prohibits this. What this means is that it may be legal to own a knife in a given state, but illegal to transport it across state lines, and that same knife may be illegal in the state to which you are traveling. The only way to be sure is to check the laws in the state to which you are traveling, and be aware that you cannot transport knives across state lines unless they meet federal standards, such as assisted-opening knives.
Another difference in state laws deals with the closure method of the knife, which the federal law does not address. If the blade closes with an assist, such as a “detent,” many states automatically classify it as an assisted-opening knife rather than an illegal switchblade. The federal law does not make this distinction.
In summary, assisted opening knives are legal in all states and can be transported across state lines without risking illegal activity.
Disclaimer: Laws are constantly changing, only a lawyer can provide you with specific advice to rely on. We are not responsible if the info above becomes inaccurate.